Is it permissible to enter a shopping website that displays pictures of naked women, knowing beforehand that these pictures exist, and does it entail sin if I guide others to this website?

There appears to be no impediment to purchasing from websites that include forbidden images, due to their widespread prevalence, unless an alternative with the same specifications and prices is available, while it is obligatory to avert one's gaze from the forbidden images as much as possible. Guiding people to such websites is permissible and does not constitute aiding in sin.